Timo, I can confirm observing the same behavior. Your email thread here was very helpful in that it gave me two workarounds: (1) service libvirtd restart (2) make some background keepalive ping. I'm hosting on a RHEL 6.4 system with similar version numbers: [root at redpant centosimage]# rpm -qa|egrep '(virt|kvm)' libvirt-python-0.10.2-18.el6_4.2.x86_64 libvirt-0.10.2-18.el6_4.2.x86_64 virt-manager-0.9.0-18.el6.x86_64 virt-viewer-0.5.2-18.el6_4.2.x86_64 virt-top-1.0.4-3.15.el6.x86_64 qemu-kvm-0.12.1.2-2.355.el6_4.2.x86_64 python-virtinst-0.600.0-15.el6.noarch virt-what-1.11-1.2.el6.x86_64 virt-who-0.8-5.el6.noarch libvirt-java-devel-0.4.9-1.el6.noarch libvirt-devel-0.10.2-18.el6_4.2.x86_64 libvirt-client-0.10.2-18.el6_4.2.x86_64 libvirt-java-0.4.9-1.el6.noarch Mojo -- Morris Jones Monrovia, CA http://mojo.whiteoaks.com